Volume 22, Issue 3 (March 2022)
Modares Mechanical Engineering 2022, 22(3): 191-200 |
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adabi R, Fathali M, Pouryoussefi G, doostmahmoudi A, amiri tayebi M. Experimental Investigation of Isotropic Flow Generated by Grid in Subsonic Wind Tunnel and Measurement of Characteristics of Turbulent Flow. Modares Mechanical Engineering 2022; 22 (3) :191-200
URL: http://mme.modares.ac.ir/article-15-55027-en.html
URL: http://mme.modares.ac.ir/article-15-55027-en.html
Reza Adabi1 
, Mani Fathali1 , Gholamhosein Pouryoussefi * 2, Alireza Doostmahmoudi1 , Mostafa Amiri tayebi1
, Mani Fathali1 , Gholamhosein Pouryoussefi * 2, Alireza Doostmahmoudi1 , Mostafa Amiri tayebi1
1- Department of Aerospace Engineering, K.N. Toosi University of Technology, Tehran, Iran.
2- Department of Aerospace Engineering, K.N. Toosi University of Technology, Tehran, Iran. ,pouryoussefi@kntu.ac.ir
2- Department of Aerospace Engineering, K.N. Toosi University of Technology, Tehran, Iran. ,
Abstract: (1654 Views)
In this research, the turbulent isotropic flow has been experimentally investigated. Hence, two different grids are made and a contraction channel is installed behind it inside the subsonic wind tunnel to generate an isotropic turbulence flow. The grids with mesh sizes of 2/54 cm and 5/08 cm were cut on the wood with obstruction ratio of 0/34 and 0/17, respectively. One-dimensional hot wire was used to determine the perturbation velocities in the direction of flow, and an approximation was used to determine the components of other directions. At speeds of 5 m/s and 10 m/s, experiments were performed for each of the grids, which range from a Reynolds number of 8500 to about 33000. To determine the onset of the isotropic location, methods of velocity skewness, kurtosis, turbulence intensity, dissipation rate, and longitudinal scales such as Kolmogorov and Taylor lengths were used. For skewness and kurtosis, the numbers show 0 and 3, respectively, which indicate the isotropic flow. Results showed that with increasing the velocity, the isotropy of the flow was delayed. Also, in a grid with a lower obstruction ratio, the intensity of turbulence will be less near the grid, but as it moves away from the grid, the intensity of turbulence will increase.
Keywords: Isotropic turbulence, Homogeneous flow, Grid, Obstruction ratio, Contraction channel, Wind tunnel
Article Type: Original Research |
Subject:
Experimental Fluid Mechanics
Received: 2021/08/22 | Accepted: 2021/10/12 | Published: 2022/01/30
Received: 2021/08/22 | Accepted: 2021/10/12 | Published: 2022/01/30
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